distributors and ICM (Page 3/3)
theogre JAN 26, 08:56 PM

quote
Originally posted by sledcaddie:
Who knew there was so much to learn about heat sink grease? Thanks, Ogre! I will try the Permatex green.

Actually is not much to HSG to know for most cases.

Biggest problem is PC world w/ vendors hyping whatever and users including "expects" believing the Hype.

Like nearly all "Silver HSG" has No Silver in them. Most are Aluminum, Al Oxides and other things w/ carrier oil.
Including Current Arctic Silver 5... Zinc Oxide, Boron Nitride, Aluminum Oxide Source: http://arcticsilver.com/PDF/AS5_SDS.pdf And still want High $ for a Fraction of 1 ounce.

Meanwhile can get...
2oz Tube white HSG at mcmaster.com for $17
100g(~3.5oz) white HSG at amazon $16
And many other places sell larger packs for > $, often a lot > $

Only thing is often can't use any silicone oil/grease in direct contact w/ silicone chips like many GPU don't have metal covers.
Some non-silicone HSG are more expensive.

I use PBG because can use it for indented job and other things and does care if takes Years to Decades to use it.
Larger or smaller HSG amounts can separate oil out and go "bad" sitting in the package.
Same problem w/ many other "car" grease even some Moble1 syn grease. More so when loaded in most grease guns sitting months to years DIY trying using up a tube. (Big spring can squeezes oil out even if storing normally oil stays put w/ a tube on a self.) Another example, Many have soft tubes of White Grease for cars etc does same thing sitting for months to years.
Would do their job but when have little/no carrier oil to letting them flow make it hard or impossible to use...
theogre JAN 26, 09:25 PM

quote
Originally posted by pmbrunelle:
I was using Thermalloy 250G (yellow tube) heat sink grease under a 2.8 ICM.

It worked, but it needed to be wiped clean and reapplied as part of an annual tuneup.

When I tried to stretch the maintenance interval, problems arose around 2 years. After 2 years, I had the ignition cutting out, and I found water trapped underneath the ICM (no more close contact between ICM and distributor base).

Is another Zinc Oxide compound. https://www.farnell.com/datasheets/3148669.pdf

HSG won't cause surfaces to loosen or other problems like that.

Iffy screws and/or Dist base can let screws to back out from vibration and heat cycling. Any oil including Carrier Oil in the HSG might make this easier.
Many have Black Oxide coated screws there that cause problems too. While that prevent rust, have problems as a Ground. GM has many TSBs to remove the coating or replace the screws.
sledcaddie JAN 27, 07:43 PM
Replace the black-coated screws with what? Stainless steel?
Pyrthian JAN 27, 07:48 PM
there is also the dist shaft. removing the whole dist assembly, removing the roll pin from the shaft, and cleaning the actual shaft and making it spin free again. I know mine was pretty sticky when I first pulled it. that stickiness makes heat. after doing that, I never had to replace my ICM again. tho, I did go to a 7730 and coil ack ignition a while later.
pmbrunelle JAN 27, 08:00 PM

quote
Originally posted by Patrick:

How'd it get in there?



Condensation? Maybe from washing the engine bay?

I don't have a good explanation for that, but water between the ICM and distributor means that were was enough of a gap that would cause poor heat transfer.


quote
Originally posted by theogre:
I use PBG because can use it for indented job and other things and does care if takes Years to Decades to use it.
Larger or smaller HSG amounts can separate oil out and go "bad" sitting in the package.
Same problem w/ many other "car" grease even some Moble1 syn grease. More so when loaded in most grease guns sitting months to years DIY trying using up a tube. (Big spring can squeezes oil out even if storing normally oil stays put w/ a tube on a self.) Another example, Many have soft tubes of White Grease for cars etc does same thing sitting for months to years.
Would do their job but when have little/no carrier oil to letting them flow make it hard or impossible to use...



Usually grease separation is a reversible process. At work we have 55 gallon drums of grease, and sometimes the oil can separate. Stirring the contents with a stick makes it good as new. Some greases seem to separate more easily than others.

Stirring the contents of a grease gun tube may prove to be tricky though.


quote
Originally posted by theogre:
Iffy screws and/or Dist base can let screws to back out from vibration and heat cycling. Any oil including Carrier Oil in the HSG might make this easier.
Many have Black Oxide coated screws there that cause problems too. While that prevent rust, have problems as a Ground. GM has many TSBs to remove the coating or replace the screws.



You can install the ICM with heat sink compound, and then remove it immediately as a test. If you see the white paste close to the screw hole, you can wipe away and start over again, until you're able to reliably install the ICM without getting heat sink compound on the threads.

I guess I would suggest liquid anaerobic threadlocker for something like this. It won't interfere with electrical conductivity, it will prevent corrosion (assuming the screws were cleaned to begin with), and it helps prevent screws from unscrewing. Once the threadlocker has cured (hours to days), it won't matter if any carrier oil seeps towards the threads.
theogre JAN 29, 12:03 PM

quote
Originally posted by pmbrunelle:
Usually grease separation is a reversible process. At work we have 55 gallon drums of grease, and sometimes the oil can separate. Stirring the contents with a stick makes it good as new. Some greases seem to separate more easily than others.

Stirring the contents of a grease gun tube may prove to be tricky though.

Grease gun tubes are often stable stored on a self. Often for years...
Once loaded in a gun, the big spring for 14oz cap or bigger drives out carrier oil and other thin parts out and gun leaks oil on everything and whatever left is often "bad."
If you pull the tube can use the paste for somethings but not going thru zerk and other small holes w/ many greases.

Small 3oz cap grease guns can have same problem but have smaller springs so less of this happening but have to keep in plastic bag to stop drips staining whatever touches.

Many have White grease and more in soft plastic tube that separate and knead the tube can mix the stuff so works ok again.
If those leak oil out because cap is loose or tube w/ small hole on sides, the product is often a HAZMAT waste.

Examples:
I had a very old silicone/dielectric grease in soft metal tube and got a very small hole and leaked oil out and then just solids and won't even flow to push out of the tube.
30+ year old white grease in plastic tube separate oil but oil stay in the tube so can use it but messy.
14oz tube Mobil1 in a gun leaked red oil on everything until gone then grease paste left won't even flow thru the gun.

5 - 55gl bulk product often won't care if separate some. If separates a lot, try "paint" mixer and drill. Make sure can reach bottom of container where most systems pick up the product. Many bulk systems have mixers build into them for product likes to separate quickly.
Skybax JAN 29, 12:17 PM

quote
Originally posted by Pyrthian:

there is also the dist shaft. removing the whole dist assembly, removing the roll pin from the shaft, and cleaning the actual shaft and making it spin free again. I know mine was pretty sticky when I first pulled it. that stickiness makes heat.



That is one of several reasons its recommended to replace the pickup coil when replacing an ICM, because it forces the overhaul/maintenance of the distributor shaft.

[This message has been edited by Skybax (edited 01-29-2022).]

sledcaddie JAN 31, 07:39 PM
I just received my new GM ignition control module (from Rock Auto). The box shows that it is made in U.S.A. It also shows the date of 1995. Maybe this is a NOS from roughly, the Fiero years.